and Somkiat Piyatiratitivorakul2
1 Fellow of the Royal Institute, Acedamy of Science
Presented at the Royal Institute on the 21 July 2010.
2 Center of Excellence for Marine Biotechnology Department of Marine Science
Faculty of Science Chulalongkorn University Bangkok, Thailand
Betaine or trimethylglycine functions as a methyl group donor. Sugar beet is the natural source of betaine. A commercial aquafeed additive using betaine as a main source is produced by the trade name of Finnstim. Other amino acids inclusions are glycine, alanine, isoleucine, leucine and valine. The composition is proprietary and is said to be the result of empirical experimentation. The role of Finnstim as a fish feed attractant was very well documented. However, further studies are needed to test its effectiveness as a feed attractant in shrimps. The current paper studied the role of Finnstim in improving palatability of high plant protein shrimp feed. Three levels of Finnstim, i.e. 0%, 0.75% and 1.5%, were tested using two basal feeds. One was a generalized Thai shrimp feed comprised mostly of animal protein and another was a high plant protein feed. This made a total of 6 treatment diets. The experimental feeding trials were conducted with juvenile Penaeus monodon in 3 replications for 8 weeks. The proximate analysis of the six treatment diets revealed that protein content in plant protein diets were approximately 3% lower than in the animal protein diets. Addition of Finnstim resulted in a 1-2% increase of protein in the basal diets depending on the amount added. This evidence showed that Finnstim protein was quite concentrated. Covariance analysis showed significant differences between the growth slopes of the six treatments. However, the growth slopes of the plant protein diet +1.5% Finnstim and the basal animal protein diet did not differ significantly. Addition of 1.5% Finnstim to the plant protein diet significantly improved the food conversion ratio, but the diet was still a little inferior to the animal protein diet. Furthermore, the addition of Finnstim in both basal diets did not significantly improve the survival rates of shrimps, which were a little lower in the plant protein diet groups than animal protein diet groups. Nevertheless, the addition of 1.5% Finnstim in plant protein diet resulted in survial rates comparable with the animal protein diet without Finnstim. In conclusion, the addition of 1.5% Finnstim to high plant protein feed could improve palatability to a level similar to the generalized Thai shrimp feed.
Key words: amino acids, betaine, Finnstim, Penaeus monodon